A possible outbreak of polar stratospheric clouds (PSCs) is underway around the Arctic Circle. Unlike normal grey-white clouds, which hug Earth's surface at altitudes of only 5 to 10 km, PSCs float through the stratosphere (25 km) and they are fantastically colorful. Ivar Marthinusen sends this picture of the phenonenon from Skedsmokorset, Norway...MORE
